the described genera of Sguamariee, with the exception of Peys- 
sonnelia), I fear to continue to associate it with plants which 
may have very different cysfocarps. Nor am I quite certain 
whether to regard what I have above described for cystocarps 
as such in truth; or whether they may not rather be antheridia. 
‘They have indeed a good deal the structure of the cystocarps of 
Scinaia ; but they still more nearly resemble the antheridia of 
Callithamnion and Griffithsia. 
Unfortunately the ¢e¢raspores of our parasite are unknown. 
It is quite uncertain, therefore, whether it be most nearly related 
to Actinococcus, of which it has the habit, or to Petrocelis or 
Cruoria. Under these circumstances 1 am almost forced to 
place it, provisionally, in a separate genus. 
Fig. 1. RHODOPELTIS AUSTRALIS, growing on a branch of Amphiroa australis, 
—the natural size. 2. Vertical section through the fronds of both plants. 
3. Vertical filaments of the parasite. 4. One of its cystocarps. 5. Fila- 
ments from the same :—magnified. 
